MANCHESTER — A public hearing on design changes to the proposed tennis courts in front of Memorial School drew more confusion than definitive answers.

After Conservation Commission members grappled with a paper trail of plan revisions and complex drawings, they decided to continue Tuesday night's hearing. They also planned a site visit and requested a comprehensive set of plans in order to form a clearer picture of the proposed changes.

The proposed tennis courts are part of the $49 million middle and high school construction project on Lincoln Street. The Conservation Commission previously denied a permit for the project, citing lack of evidence that a different site with less environmental impact was not available at an equivalent cost. The decision was appealed to the state Department of Environmental Protection by the Manchester Essex Regional School District. While the state agency ruled in favor of the schools, the project needs local permits to continue.

Ben Gary, a representative from the site planning and environmental design firm Marshall/Gary LLC, presented the project revisions.

One project change was the addition of a rain garden, a planted area that would filter and treat runoff from the upper part of Lincoln Street. Also, Gary said, the grass swale was widened and stone would be placed in areas to prevent erosion. He said revised drainage calculations, which would incorporate a larger area, were given to the commission's hired consultant, Brian Marchetti of the engineering firm Tetra Tech Rizzo.

Marchetti said the project, as revised, had no negative impact on flooding and was in compliance with local wetland bylaws.

Commission member Tom Walker asked if the changes made the plans significantly different from those the Department of Environmental Protection used as the basis for its decision on the schools' appeal.

Attorney Richard Nylen, who represents the schools, said it would be up to the state agency to decide.

Marchetti and Gary's findings about the impact on groundwater and stormwater runoff were also disputed by professionals representing the Concerned Citizens of Manchester, a group opposed to the tennis courts. Concerned Citizens says the project could contaminate the nearby Lincoln Street well, a town water supply, and create flooding and stormwater runoff problems.

Marchetti said soil borings as deep as 13 feet did not run into groundwater, so excavation for the project, which is proposed to go down 6 feet, should not be a problem. However, Frederick Geisel, an engineer hired by Concerned Citizens, said soil borings taken in January near the culvert showed the water table at 13 inches below the surface.

Gary said stormwater runoff would flow away from the tennis courts because of berms around the area.

However, attorney John Hamilton, who represents Concerned Citizens, said his client asserts that the berm along Lincoln Street doesn't divert water, and that water flows over it in small storms.

Confusion and frustration surfaced throughout the hearing as commissioners were unsure of where revisions were indicated in the plans, which consisted of original submissions from July and separate revised submissions.

"We've basically been putting Post-Its on this thing and we need a complete, comprehensive submittal," commission member Amy Burbott said.

Lisa Press, conservation administrator to the commission, pointed out how confusing the drawings were as well.

"Can you look at this and tell me you know what's going on?" said Press. "I look at this and see a mess."

She said that, without Gary's explanations, she would not be able to match the plans' depictions to the actual site.

Gary said the complexity of engineering plans can make them difficult to read, and cited the complexity of the situation being presented.

"We're open to any suggestions or questions or comments to make it more readable," he said.

Commission Chairman Paul Cullinane said it was important to have a set of plans with everything on it at a more visible scale, both for the purpose of the commission's vote and for public record.

The commission decided to walk the site during the next rainstorm to get a better picture of water flow on site. Gary said he would stake different aspects of the proposed design to provide a sense of the layout. Tentative plans were made for Saturday after a resident said the forecast predicted rain.

The commission also asked that a full set of updated plans be submitted by Nov. 5. Members requested that some additional diagrams, including a cross section of the whole project, be added for clarification. Professionals representing Concerned Citizens' point of view, who will make a presentation at the next public hearing, were also asked to submit materials by Nov. 5.

The hearing will continue during the Conservation Commission's Nov. 12 meeting at 7:30 p.m. in Town Hall, room 5.

Amanda Flitter can be reached at gt_reporter@gloucestertimes.com.